Study of GA-GCB Enzyme Replacement Therapy in Type 1 Gaucher Disease Patients Previously Treated With Imiglucerase

Type 1 Gaucher disease, the most common form, accounts for more than 90% of all cases and does not involve the CNS. Typical manifestations of type 1 Gaucher disease include hepatomegaly, splenomegaly, thrombocytopenia, bleeding tendencies, anemia, hypermetabolism, skeletal pathology, growth retardation, pulmonary disease, and decreased quality of life. Gene-Activated® human glucocerebrosidase (GA-GCB; velaglucerase alfa) is produced in a continuous human cell line using proprietary gene-activation technology and has an identical amino acid sequence to the naturally occurring human enzyme. GA-GCB contains terminal mannose residues that target the enzyme to the macrophages-the primary target cells in Gaucher disease. This study was designed to determine the safety of GA-GCB in men, women, and children with Type 1 Gaucher disease who were previously treated with imiglucerase. Each participant's duration of treatment will be 12 months.

Inclusion criteria

Includes:

• The participant has a documented diagnosis of type 1 Gaucher disease, as determined by deficient glucocerebrosidase (GCB) activity relative to normal as measured in leukocytes or by genotype analysis and the participant/legal guardian is willing and able to provide written informed consent prior to initiating any study-related procedures
• The participant has received consistent treatment with imiglucerase at a dose ≤ 60 U/kg and ≥ 15 U/kg every other week for a minimum of 30 consecutive months. Participants who are anti-imiglucerase antibody positive will be allowed to enter this study
• The participant is at least 2 years of age
• Female participants of child-bearing potential agree to use a medically acceptable method of contraception. Male participants must agree to use a medically acceptable method of birth control
• Participant must be sufficiently co-operative to participate in the study as judged by the Investigator.

Exclusion criteria

Includes:

• The participant has type 2 or 3 Gaucher disease or is suspected of having type 3 Gaucher disease
• The participant has received treatment with any investigational drug or device within the 30 days prior to study entry; such use during the study is not permitted
• Participant is HIV positive
• Participant is hepatitis B/C positive
• The participant presents with sustained iron, folic acid and/or vitamin B12 deficiency-related anemia during Screening
• The participant, participant's parent(s), or participant's legal guardian(s) is/are unable to understand the nature, scope, and possible consequences of the study
• The participant has a significant comorbidity that might affect study data or confound the study results
• The participant is unable to comply with the protocol or is otherwise unlikely to complete the study, as determined by the Investigator
• The participant has experienced an anaphylactic/anaphylactoid reaction during treatment with imiglucerase
• The participant has received miglustat during the 6 months prior to study enrollment
• The participant has an active, clinically significant spleen infarction
• The participant has active, progressive bone necrosis
• The participant is a pregnant and/or lactating female